Torque transmission mechanism

Abstract

A torque transmission mechanism includes a first member having a cylindrical shape and configured to be rotatable around a rotation axis, the first member including an outer peripheral surface provided with a first groove having a zigzag shape extending around the rotation axis, a second member having an annular shape surrounding the first member and configured to be rotatable around the rotation axis, the second member including an inner peripheral surface provided with a second groove having a zigzag shape extending around the rotation axis, one or more first rolling members disposed in and configured to be rollable in the first groove and in the second groove, and a first regulating member disposed between the first member and the second member and configured to allow movement of the first rolling members along the rotation axis and regulate movement of the first rolling members around the rotation axis.

What is claimed is: 
     
         1 . A torque transmission mechanism, comprising:
 a first member having a cylindrical shape and configured to be rotatable around a rotation axis, the first member including an outer peripheral surface provided with a first groove having a zigzag shape extending around the rotation axis;   a second member having an annular shape surrounding the first member and configured to be rotatable around the rotation axis, the second member including an inner peripheral surface provided with a second groove having a zigzag shape extending around the rotation axis;   one or more first rolling members disposed in the first groove and in the second groove and configured to be rollable in the first groove and in the second groove; and   a first regulating member disposed between the first member and the second member and configured to allow movement of the first rolling members along the rotation axis and regulate movement of the first rolling members around the rotation axis.   
     
     
         2 . The torque transmission mechanism according to  claim 1 , wherein
 the first groove and the second groove have a periodic wave shape including one or more mountain portions and valley portions, and   a number of the mountain portions and a number of the valley portions of the first groove are different from the number of the mountain portions and the number of the valley portions of the second groove, respectively.   
     
     
         3 . The torque transmission mechanism according to  claim 2 , wherein
 an outer peripheral surface of the second member is provided with a third groove having a zigzag shape extending around the rotation axis,   the torque transmission mechanism further includes   a third member having an annular shape surrounding the second member and configured to be rotatable around the rotation axis, the third member including an inner peripheral surface provided with a fourth groove having a zigzag shape extending around the rotation axis,   one or more second rolling members disposed in the third groove and in the fourth groove and configured to be rollable in the third groove and in the fourth groove, and   a second regulating member that is disposed between the second member and the third member, allows movement of the second rolling members along the rotation axis, and regulates movement of the second rolling members around the rotation axis,   the third groove and the fourth groove have a periodic wave shape including at least one of the mountain portions and the valley portions, and   the number of the mountain portions and the number of the valley portions of the third groove are different from the number of the mountain portions and the number of the valley portions of the fourth groove, respectively.   
     
     
         4 . The torque transmission mechanism according to  claim 2 , further comprising:
 a fourth member having a cylindrical shape and configured to be rotatable around the rotation axis, the fourth member including an outer peripheral surface provided with a fifth groove having a zigzag shape extending around the rotation axis;   a fifth member having an annular shape surrounding the fourth member and configured to be rotatable around the rotation axis, the fifth member including an inner peripheral surface provided with a sixth groove having a zigzag shape extending around the rotation axis;   one or more fourth rolling members disposed in the fifth groove and in the sixth groove and configured to be rollable in the fifth groove and in the sixth groove; and   a third regulating member disposed between the fourth member and the fifth member and configured to allow movement of the fourth rolling members along the rotation axis and regulate movement of the fourth rolling members around the rotation axis; and   a coupling member configured to couple the second member and the fourth member so as to be rotatable around the rotation axis, wherein   the fourth member and the fifth member are disposed side by side with the first member and the second member in a direction of the rotation axis,   the fifth groove and the sixth groove have a periodic wave shape including at least one of the mountain portions and the valley portions, and   the number of the mountain portions and the number of the valley portions of the fifth groove are different from the number of the mountain portions and the number of the valley portions of the sixth groove, respectively.   
     
     
         5 . The torque transmission mechanism according to  claim 4 , wherein
 each of the first groove and the fifth groove includes the same number of the mountain portions and the valley portions,   each of the second groove and the sixth groove includes the same number of the mountain portions and the valley portions, and   at least one of the first rolling members is configured to be positioned at the mountain portions of the first groove when at least one of the fourth rolling members is positioned at the valley portions of the fifth groove, and is configured to be positioned at the mountain portions of the second groove when at least one of the fourth rolling members is positioned at the valley portions of the sixth groove.   
     
     
         6 . The torque transmission mechanism according to  claim 1 , wherein
 the first rolling members have a spherical shape.   
     
     
         7 . The torque transmission mechanism according to  claim 1 , wherein
 the first rolling members include one rolling member and another rolling member, and   the first regulating member include one regulating portion that allows movement of the one rolling member along the rotation axis and regulates movement of the first rolling members around the rotation axis, and another regulating portion that allows movement of the another rolling member along the rotation axis and regulates movement of the another rolling member around the rotation axis.   
     
     
         8 . The torque transmission mechanism according to  claim 1 , further comprising a first bearing portion disposed between the first member and the first regulating member and configured to hold the first member so as to be rotatable with respect to the first regulating member. 
     
     
         9 . The torque transmission mechanism according to  claim 1 , further comprising a second bearing portion disposed between the second member and the first regulating member and configured to hold the second member so as to be rotatable with respect to the first regulating member. 
     
     
         10 . The torque transmission mechanism according to  claim 1 , wherein
 the outer peripheral surface of the first member is provided with a first corresponding groove having a zigzag shape corresponding to the first groove side by side with the first groove in a direction of the rotation axis,   the inner peripheral surface of the second member is provided with a second corresponding groove having a zigzag shape corresponding to the second groove side by side with the second groove in the direction of the rotation axis,   the torque transmission mechanism further includes one or more third rolling members disposed in the first corresponding groove and in the second corresponding groove and configured to be rollable in the first corresponding groove and in the second corresponding groove, and   the first regulating member further allows movement of the third rolling members along the rotation axis and regulates movement of the third rolling members around the rotation axis.   
     
     
         11 . The torque transmission mechanism according to  claim 8 , wherein
 the first groove and the first corresponding groove each have a periodic wave shape including the same number of the mountain portions and the valley portions,   the second groove and the second corresponding groove each have a periodic wave shape including the same number of the mountain portions and the valley portions, and   at least one of the first rolling members is configured to be positioned at the mountain portions of the first groove when at least one of the third rolling members is positioned at the valley portions of the first corresponding groove, and to be positioned at the mountain portions of the second groove when the at least one of the third rolling members is positioned at the valley portions of the second corresponding groove.   
     
     
         12 . The torque transmission mechanism according to  claim 11 , wherein
 the first groove and the first corresponding groove are disposed such that the mountain portions of the first groove and the valley portions of the first corresponding groove face each other, and   the second groove and the second corresponding groove are disposed such that the mountain portions of the second groove and the valley portions of the second corresponding groove face each other.   
     
     
         13 . The torque transmission mechanism according to  claim 1 , wherein
 the first groove and the second groove have a triangular wave shape.